1➤ ** State Henry's law.**

**=> Ans. Statement of Henry's law: It states that the solubility of a gas in water at constant temperature is proportional to the pressure of the gas above the solution.**

2➤ ** State Raoult's law.**

**=> Ans. Statement of Raoult's law: The law states that, at constant. temperature, the partial vapour pressure of any volatile component of a solution is equal to the product of vapour pressure of the pure component and the mole fraction of that component in the solution.**

3➤ **
(3) Give mathematical expression for Ostwald's dilution law.**

**=> Ans. Ostwald's dilution law is expressed as KOR KV(1-x) K= where K is a dissociation constant of a weak electrolyte, Cx² (1-x) is degree of dissociation, Cis concentration in mol dm Vis dilution in dm' mol-.**

4➤ **
State the first law of thermodynamics in different ways.**

**=> Ans. The first law of thermodynamics is based on the principle of conservation of energy and can be stated in different ways as follows: (1) Energy can neither be created nor destroyed, however, it may be converted from one form into another. (2) Whenever, a quantity of one kind of energy is consumed or disappears, an equivalent amount of another kind of energy appears. (3) The total mass and energy of an isolated system remain constant, although there may be interconservation of energy from one form to another. (4) The total energy of the universe remains constant.**